Several methods are known for making complete plastic eyeglass frames having the front portion thereof strengthened internally by a continuous metal blade member embedded in the thickness of the contour of the glass holding seats and in the thickness of the nose bridging portion.
These known methods, however, are not completely satisfactory.
In fact, the placing, according to the conventional manufacturing methods, of the metal blade in the glass holding seats formed in the body of the front portion of the eyeglass frame generally involves adoption of special and frequently intricate techniques, and the use of specifically designed tools, such as special clamping devices, abutting planes and the like, which in addition to remarkably increasing the cost, require rather prolonged machining times, with a consequent reduction in the output.
Furthermore, these known methods do not permit an easy production of plastic eyeglass frames allowing for adjustable and swinging nose bearing elements to be simply and quickly fixed thereto, and which permit the eyeglasses to be fitted to a broad range of nose size and shapes.
Finally the known methods provide eyeglass frames of poor flexibility with consequent difficulties in the fitting of the glasses which requires heating the overall eyeglass contour or profile to expand to the glass size and then insertion of the glass, this latter being locked in position as the eyeglass profile cools down. This technique involves both great precision in the making of the glass profile with respect to the related seat in order to exploit the slight profile expansion, for the insertion and the locking, and the practical impossibility for the user of replacing the glasses by others of different types, depending on his needs.